Controlling wireless power transfer systems

ABSTRACT

Methods, systems, and devices for operating wireless power transfer systems. One aspect features a wireless energy transfer system that includes a transmitter, and a receiver. The transmitter has a transmitter-IMN and is configured to perform operations including performing a first comparison between a characteristic of a power of the transmitter and a target power. Adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter. The receiver has a receiver-IMN and is configured to perform operations including determining an efficiency of the wireless energy transfer system at a second time based on power data from the transmitter. Performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time. Adjusting, based on the second comparison, a reactance of the receiver-IMN.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/422,554, filed on Feb. 2, 2017, which claimspriority to U.S. Provisional Patent Application Nos. 62/290,325, filedon Feb. 2, 2016, and 62/379,618 filed on Aug. 25, 2016, the entirecontents of which are incorporated herein by reference.

BACKGROUND

Wireless power transfer systems operate over a wide range of couplingfactors k, load conditions, and environmental conditions. Variations inthese parameters affect the efficiencies of wireless power transfersystems. Wireless power transfer systems can include impedance matchingnetworks to improve power transfer capability and efficiency. Obtaininggood performance in a wireless power transfer system over such a widerange of conditions is challenging for traditional impedance matchingnetworks.

SUMMARY

In general, the disclosure features wireless power transmission controlsystems that synchronously tune a wireless power transmitter andreceiver to adapt to changing system, parameters, environmentalparameters, or both. The wireless power transmission control systemsdescribed herein can be used in a variety of contexts, includingimplantable devices, cell phone and other mobile computing devicechargers, and chargers for electric vehicles.

In a first aspect, the disclosure features a wireless energy transmitterthat has a transmitter-impedance matching network (IMN). The transmitteris configured to perform operations including performing a firstcomparison between a characteristic of a power of the transmitter and atarget power. Adjusting, based on the first comparison, a reactance ofthe transmitter-IMN to adjust the power of the transmitter. Transmittingpower data that indicates the power of the transmitter to a wirelessenergy receiver.

In a second aspect, the disclosure features a wireless energy receiverthat has a receiver-IMN. The receiver is configured to performoperations including determining an efficiency of a wireless energytransfer system at a second time based on power data from a wirelessenergy transmitter. Performing a second comparison between theefficiency at the second time and an efficiency of the wireless energytransfer system at a first time, the first time being prior to thesecond time. Adjusting, based on the second comparison, a reactance ofthe receiver-IMN.

In a third aspect, the disclosure features a wireless energy transfersystem that includes an energy transmitter, and an energy receiver. Thetransmitter has a transmitter-IMN. The transmitter is configured toperform operations including performing a first comparison between acharacteristic of a power of the transmitter and a target power.Adjusting, based on the first comparison, a reactance of thetransmitter-IMN to adjust the power of the transmitter. The receiver hasa receiver-IMN. The receiver is configured to perform operationsincluding determining an efficiency of the wireless energy transfersystem at a second time based on power data from the transmitter.Performing a second comparison between the efficiency at the second timeand an efficiency of the wireless energy transfer system at a firsttime, the first time being prior to the second time. Adjusting, based onthe second comparison, a reactance of the receiver-IMN.

The first aspect and the second aspect can operate together in a systemsuch as the system of the third aspect. Furthermore, these and thefourth through sevenths aspects can each optionally include one or moreof the following features.

In some implementations, adjusting the reactance of the receiver-IMNincludes adjusting the reactance of the receiver-IMN by a variablereactance adjustment value.

In some implementations, the first comparison and adjustment to thereactance of the transmitter-IMN occur iteratively until thecharacteristic of the power is within a threshold value of the targetpower.

In some implementations, adjusting the reactance of the receiver-IMNincludes, in response to the efficiency at the second time being lessthan the efficiency at the first time, negating a reactance adjustmentvalue. Adjusting the reactance of the receiver-IMN includes adjustingthe reactance of the receiver-IMN by the negated reactance adjustmentvalue.

In some implementations, adjusting the reactance of the transmitter-IMNincludes, in response to the power being less than the target power,adjusting the reactance of the transmitter-IMN by a first reactanceadjustment value. In response to the power being greater than the targetpower, adjusting the reactance of the transmitter-IMN by a second,different reactance adjustment value.

In some implementations, the first reactance adjustment value is equalin magnitude and opposite in sign to the second reactance adjustmentvalue

In some implementations, the first comparison is between a power factorof the power of the transmitter and a target power factor. Theoperations of the transmitter can include a third comparison between amagnitude of the power and a target power magnitude, wherein the thirdcomparison follows the first comparison, and adjusting, based on thethird comparison, a bus voltage of the transmitter to adjust the powerof the transmitter.

In some implementations, the power factor is represented by a phaserelationship between a transmitter voltage and a transmitter current.

In some implementations, the first comparison and adjustment of thereactance of the transmitter-IMN based on the first comparison occuriteratively until the power factor of the power is within a thresholdvalue of the target power factor.

In some implementations, the steps of performing the first comparisonand adjusting the reactance of the transmitter-IMN are iterated at afaster rate than the steps of performing the third comparison andadjusting the bus voltage.

In some implementations, the transmitter is an electric vehicle chargerand wherein the receiver is a coupled to a power system of an electricvehicle.

In some implementations, the operations of the transmitter includeshutting down the wireless energy transfer system by reducing the targetpower to zero.

In some implementations, the operations of the transmitter includeshutting down a power inverter in the transmitter.

In some implementations, the operations of the transmitter includestarting up the transmitter by adjusting the reactance of thetransmitter-IMN to a maximum value.

In some implementations, the operations of the transmitter includestarting up the transmitter by adjusting a frequency of an inverter to atarget frequency.

In some implementations, the operations of the receiver include startingup the receiver by adjusting the reactance of the receiver-IMN to aminimum value.

In some implementations, the operations of the receiver include startingup the receiver by adjusting the reactance of the receiver-IMN from amaximum value to a minimum value.

In some implementations, the transmitter-IMN includes a tunable reactiveelement electrically connected between an inverter and at least onefixed reactive element, and adjusting the reactance of thetransmitter-IMN includes adjusting the tunable reactive element.

In some implementations, the receiver-IMN includes a tunable reactiveelement electrically connected between a rectifier and at least onefixed reactive element, and adjusting the reactance of the receiver-IMNincludes adjusting the tunable reactive element.

In some implementations, the steps of performing the first comparisonand adjusting the reactance of the transmitter-IMN are iterated at afaster rate than the steps of performing the second comparison andadjusting the reactance of the receiver-IMN.

In some implementations, determining the efficiency of the wirelessenergy transfer system includes receiving power data from thetransmitter, determining an output power of the receiver, andcalculating the efficiency of the wireless energy transfer system basedon the power data from the transmitter and the output power of thereceiver.

In some implementations, the operations of the transmitter includeperforming a plurality of checks that can include a check of a magnitudeof the power, a check of a power factor of the power, and a check of afrequency of an inverter in the transmitter, and in response to theplurality checks, selectively adjusting the frequency of the inverter toadjust the power of the transmitter.

In some implementations, the operations of the transmitter includeperforming a plurality of checks that can include a check of a magnitudeof the power and a check of a phase shift of an inverter of thetransmitter, in response to the plurality checks, selectively adjustingthe phase shift of the inverter to adjust the power of the transmitter.

In some implementations, the operations of the transmitter include,before adjusting the bus voltage, verifying that the bus voltage isgreater than a minimum bus voltage.

In some implementations, the first comparison is between a power factorof the power of the transmitter and a target power factor. Theoperations of the transmitter can include performing a third comparisonbetween a magnitude of the power and a target power magnitude,adjusting, based on the third comparison, the reactance of thetransmitter-IMN to reduce the power of the transmitter.

In some implementations, the first comparison is between a power factorof the power of the transmitter and a target power factor. Theoperations of the transmitter can include performing a third comparisonbetween a magnitude of the power and a target power magnitude, andadjusting, based on the third comparison, a frequency of an inverter ofthe transmitter to reduce the power of the transmitter.

In some implementations, the first comparison is between a power factorof the power of the transmitter and a target power factor. Theoperations of the can include performing a third comparison between amagnitude of the power and a target power magnitude, and adjusting,based on the third comparison, a phase shift of an inverter of thetransmitter to reduce the power of the transmitter.

In some implementations, the transmitter includes an inductive coilcoupled to at least portion of the transmitter-impedance matchingnetwork to form a transmitter resonator.

In some implementations, the receiver includes an inductive coil coupledto at least portion of the receiver-impedance matching network to form areceiver resonator.

In a fourth aspect, the disclosure features the subject matter describedin this specification can be embodied in methods that include theactions of tuning, by a wireless energy transmitter, a transmitter-IMNof the wireless energy transmitter to achieve a target transmitter powercharacteristic. Sending, by the wireless energy transmitter, power datathat indicates the power of the transmitter to a wireless energyreceiver. Tuning, by the wireless energy receiver and based on the powerdata, the receiver-IMN to improve an efficiency of the wireless energytransfer system.

In a fifth aspect, the disclosure features a wireless energy transmitterthat has a transmitter-IMN. The transmitter is configured to performoperations including tuning the transmitter-IMN to achieve a targettransmitter power characteristic and sending power data that indicatesthe power of the transmitter to a wireless energy receiver.

In a sixth aspect, the disclosure features a features a wireless energyreceiver that has a receiver-IMN. The receiver is configured to performoperations including tuning the receiver-IMN to improve an efficiency ofthe wireless energy transfer system based on power data received from awireless energy transmitter.

In a seventh aspect, the disclosure features a wireless energy transfersystem that includes an energy transmitter, and an energy receiver. Thetransmitter is configured to perform operations including tuning thetransmitter-IMN to achieve a target transmitter power characteristic andsending power data that indicates the power of the transmitter to thewireless energy receiver. The receiver has a receiver-IMN. The receiveris configured to perform operations including tuning the receiver-IMN toimprove an efficiency of the wireless energy transfer system based onpower data received from the wireless energy transmitter.

The fifth aspect and the sixth aspect can operate together in a systemsuch as the system of the seventh aspect. Furthermore, these and thefirst through third aspects can each optionally include one or more ofthe following features.

In some implementations, the target transmitter power characteristic isa target power factor and the target transmitter power characteristic isa target power factor.

In some implementations, the power factor is represented by a phasedifference between a transmitter voltage and a transmitter current, andthe target power factor is a target phase difference.

In some implementations, the operations include adjusting, by thetransmitter, an inverter bus voltage to achieve a target powermagnitude.

In some implementations, the operations include adjusting, by thetransmitter, an inverter bus voltage to achieve a target powermagnitude.

In some implementations, the operations include performing a safetycheck prior to adjusting the transmitter-IMN. In some implementations,the safety check is an over-voltage check or an over-current check.

In some implementations, the operations include performing, by thetransmitter, a plurality of checks that can include a check of amagnitude of a transmitter power, a check of a transmitter power factor,and a check of a frequency of an inverter in the transmitter; and inresponse to the plurality checks, selectively adjusting the frequency ofthe inverter to adjust the power of the transmitter.

In some implementations, the operations include performing a pluralityof checks that can include a check of a magnitude of a transmitter powerand a check of a phase shift of an inverter of the transmitter; and inresponse to the plurality checks, selectively adjusting the phase shiftof the inverter to adjust the power of the transmitter.

In some implementations, the transmitter is an electric vehicle chargerand the receiver is a coupled to a power system of an electric vehicle.

In some implementations, the operations include adjusting, whilestarting up the transmitter, the reactance of the transmitter-IMN to amaximum value.

In some implementations, the operations include adjusting, whilestarting up the receiver, the reactance of the receiver-IMN to a minimumvalue.

In some implementations, the transmitter includes an inductive coilcoupled to at least portion of the transmitter-impedance matchingnetwork to form a transmitter resonator.

In some implementations, the receiver includes an inductive coil coupledto at least portion of the receiver-impedance matching network to form areceiver resonator.

In an eighth aspect, the disclosure features a wireless powertransmission system without bus voltage control configured to implementa control loop for tuning power transmission, where the control loopincludes: a first sub-loop to control output power of a transmitter ofthe wireless power transmission system, and a second sub-loop to tune acombined reactance of an inductor and a capacitor that couple a tankcircuit to a rectifier in a receiver of the wireless power transmissionsystem, where the second sub-loop tunes the combined reactance bymonitoring efficiency of wireless power transmission. Furthermore, thisand other implementations can each optionally include one or more of thefollowing features.

In some implementations, the second sub-loop employs aperturb-and-observe strategy to improve efficiency based on a previouspoint by tuning the combined reactance of an inductor and a capacitorthat couple a tank circuit to a rectifier in a receiver of the wirelesspower transmission system.

In some implementations, the second sub-loop is dependent on a powercomparison where output power is compared to target power at a start ofthe control loop.

In some implementations, the second sub-loop operates at the rate ofcommunication, for example, 40 Hz.

In some implementations, the control loop is characterized by:

$P_{inv} = {\frac{\frac{8}{\pi^{2}}V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}}R_{inv}}$where P_(inv) is power out of an inverter of the transmitter of thewireless power transmission system, V_(bus) is bus voltage, R_(inv) isresistance seen by the inverter, and X_(inv) is reactance seen by theinverter, and where the tuning occurs at X_(inv)=the combined reactanceof the inductor and the capacitor.

In some implementations, the first sub-loop is a local loop that doesnot communicate with another part of the wireless power transmissionsystem.

In some implementations, the first sub-loop is faster than the secondsub-loop where the first sub-loop is on order of 1 to 10 kHz.

In some implementations, the control loop includes preparing inputs,including: setting transmitter reactance to a maximum value, settingreceiver reactance to a minimum value, and where the efficiency ofwireless power transmission at time zero=0 and receiver reactance is tobe changed by a constant or variable value.

In some implementations, the control loop starts by comparing outputpower to target power. In some implementations, if the output powerequals the target power within a tolerance, then: efficiency is measuredat a time n, the efficiency at time n is compared to efficiency at aprevious time n−1, if the efficiency at time n is greater than theefficiency at the previous time n−1, then a change in receiver reactanceis added to the receiver reactance and the output power is compared tothe target power; whereas if efficiency at time n is equal to or lessthan the efficiency at the previous time n−1, then a change in receiverreactance is negated, the negated change is added to the receiverreactance, and the output power is compared to the target power.

In some implementations, if the output power does not equal the targetpower within a tolerance, then: it is determined whether the outputpower is less than the target power, if the output power is less thanthe target power, then a change in transmitter reactance is set to −δ,the change in transmitter reactance is added to the transmitterreactance, and the output power is compared to the target power; if theoutput power is greater than the target power, then the change intransmitter reactance is set to δ, the change in transmitter reactanceis added to the transmitter reactance, and the output power is comparedto the target power.

In a ninth aspect, the disclosure features a wireless power transmissionsystem with bus voltage control configured to implement a control loopfor tuning power transmission, where the control loop includes: a firstsub-loop to control phase as defined:φ=arctan(X_(inverter)/R_(inverter)), a second sub-loop to control outputpower, and a third sub-loop to tune a combined reactance of an inductorand a capacitor that couple a tank circuit to a rectifier in a receiverof the wireless power transmission system by monitoring efficiency.Furthermore, this and other implementations can each optionally includeone or more of the following features.

In some implementations, the third sub-loop employs aperturb-and-observe strategy to improve efficiency based on a previouspoint by tuning the combined reactance of an inductor and a capacitor.

In some implementations, the third sub-loop is dependent on a powercomparison and thus on the second sub-loop.

In some implementations, the third sub-loop operates at a rate ofcommunication, for example, 40 Hz (speed of WiFi).

In some implementations, the control loop can be characterized by:

$P_{inv} = {\frac{\frac{8}{\pi^{2}}V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}}R_{inv}}$where P_(inv) is power output from an inverter of the transmitter of thewireless power transmission system, V_(bus) is bus voltage, R_(inv) isresistance seen by the inverter, and X_(inv) is the reactance seen bythe inverter, and where tuning occurs at both V_(bus) and X3=X_(inv).

In some implementations, the first sub-loop is adjusted first, thesecond sub-loop is then adjusted, and the third sub-loop is thenadjusted.

In some implementations, the first sub-loop runs on the order of 1 to 10kHz.

In some implementations, the first sub-loop is a local loop and does notcommunicate with another part of the wireless power transmission system.

In some implementations, the second sub-loop is a local loop and doesnot communicate with another part of the wireless power transmissionsystem.

In some implementations, the second sub-loop runs on the order of 1 to10 kHz.

In some implementations, the control loop includes preparing inputs,including: setting transmitter reactance to a maximum value, settingreceiver reactance to a minimum value, where the efficiency of wirelesspower transmission at time zero=0, the receiver reactance is to beincreased, the transmitter reactance is to be increased, the bus voltageis to be increased, and phase is to be increased.

In some implementations, the control loop includes: comparing a phasemeasured at the inverter to a target phase, and if the phase measured atthe inverter equals the target phase, then output power is compared totarget power.

In some implementations, the third sub-loop occurs if the output powerequals the target power and includes: measuring efficiency at a time n,comparing efficiency at the time n to efficiency at a previous time n−1,if the efficiency at the time n is greater than the efficiency at theprevious time n−1 then receiver reactance is incremented; whereas if theefficiency at the time n is less than or equal to the efficiency at theprevious time n−1, then change in the receiver reactance is negated andthe negated value is added to the receiver reactance.

In some implementations, the second sub-loop occurs if the output powerdoes not equal the target power and includes: if the output power isless than the target power, increasing the bus voltage, and if theoutput power is greater than the target power, reducing the bus voltage.

In some implementations, the first sub-loop occurs if a phase measuredat inverter is not equal to a target phase and includes: if the phasemeasured at inverter is greater than a target phase, comparing receiverreactance to a minimum receiver reactance and if the receiver reactanceequals the minimum receiver reactance, then comparing the output powerto the target power; whereas if the receiver reactance does not equalthe minimum receiver reactance, decreasing the transmitter reactance;and if the phase measured at the inverter is less than the target phase,then comparing the receiver reactance to a maximum receiver reactanceand if the receiver reactance equals maximum receiver reactance thencomparing the output power to the target power whereas if the receiverreactance does not equal the maximum receiver reactance then increasingthe transmitter reactance.

Particular implementations of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. Implementations may improve the efficiency ofoperating wireless power transfer systems. Implementations may improvethe dependability of wireless power transfer systems. Implementationsmay improve robustness of wireless power transfer systems to operateover many conditions. Implementations may improve ability to achievehigher levels of power transfer over many conditions.

Embodiments of the devices, circuits, and systems disclosed can alsoinclude any of the other features disclosed herein, including featuresdisclosed in combination with different embodiments, and in anycombination as appropriate.

The details of one or more implementations of the subject matterdescribed in this specification are set forth in the accompanyingdrawings and the description below. Other features, aspects, andadvantages of the subject matter will be apparent from the description,the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B depict diagrams of an exemplary wireless powertransmission system.

FIGS. 2A-2D depict plots related to the effects of receiver X3 tuning inan exemplary wireless power transmission system.

FIG. 3 depicts a flowchart of an exemplary control process for operatinga wireless power transmission system.

FIG. 4 depicts a flowchart of another exemplary control process foroperating a wireless power transmission system.

FIGS. 5A-5C depict more detailed flowcharts of exemplary controlprocesses for operating control loop for tuning a wireless powertransmission system.

FIG. 6A depicts a flowchart of an exemplary startup process for awireless power transmission control system.

FIG. 6B depicts a flowchart of an exemplary shutdown process for awireless power transmission control system.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Wireless energy transfer systems described herein can be implementedusing a wide variety of resonators and resonant objects. As thoseskilled in the art will recognize, important considerations forresonator-based power transfer include resonator quality factor andresonator coupling. Extensive discussion of such issues, e.g., coupledmode theory (CMT), coupling coefficients and factors, quality factors(also referred to as Q-factors), and impedance matching is provided, forexample, in U.S. patent application Ser. No. 13/428,142, published onJul. 19, 2012 as US 2012/0184338, in U.S. patent application Ser. No.13/567,893, published on Feb. 7, 2013 as US 2013/0033118, and in U.S.patent application Ser. No. 14/059,094, published on Apr. 24, 2014 as US2014/0111019. The entire contents of each of these applications areincorporated by reference herein.

In some applications such as wireless power transfer, impedances seen bythe wireless power supply source and device may vary dynamically. Insuch applications, impedance matching between a device resonator coiland a load, and a source resonator coil and the power supply, may berequired to prevent unnecessary energy losses and excess heat. Theimpedance experienced by a resonator coil may be dynamic, in which case,a dynamic impedance matching network can be provided to match thevarying impedance to improve the performance of the system. In the caseof the power supply in a wireless power system, the impedances seen bythe power supply may be highly variable because of changes in the loadreceiving power (e.g., battery or battery charging circuitry) andchanges in the coupling between the source and device (caused, forexample, by changes in the relative position of the source and deviceresonators). Similarly, the impedance experienced by the deviceresonator may also change dynamically because of changes in the loadreceiving power. In addition, the desired impedance matching for thedevice resonator may be different for different coupling conditionsand/or power supply conditions. Accordingly, power transfer systemstransferring and/or receiving power via highly resonant wireless powertransfer, for example, may be required to configure or modify impedancematching networks to maintain efficient power transfer. Implementationsof the present disclosure provide startup, shutdown, and steady stateoperation processes that allow for efficient operation over the entirerange of conditions encountered in highly-resonant wireless powertransfer systems (HRWPT) system such as high-power vehicle chargingsystems, for example.

FIGS. 1A and 1B depict diagrams of an exemplary a wireless powertransfer system 100. Referring first to FIG. 1A, the system 100 includesa wireless power transmitter 102 and a wireless power receiver 104. Awirelessly powered or wirelessly charged device 112 is coupled toreceiver 104. Wirelessly powered or wirelessly charged devices 112 caninclude, for example, high-power devices such as electric vehicles orelectronic devices such as laptops, smartphones, tablets, and othermobile electronic devices that are commonly placed on desktops,tabletops, bar tops, and other types of surfaces.

For purposes of illustration, wireless power transfer system 100 will bediscussed in the context of a wireless charging system for an electricvehicle. For example, system 100 can be a HRWPT system which is requiredto operate over a wide range of coupling factors k, load conditions(such as a battery voltage), and environmental conditions that detunethe inductances of the resonators (e.g., due to spatial variations andinterfering objects). Furthermore, in order to perform wireless chargingof electric vehicles, system 100 may be required to operate with highvoltages (e.g., between 360V and 800V) and high currents (e.g., between26 A and 40 A) to achieve a suitable range of power (e.g., 0 to 3.7 kW,0 to 7.7 kW, 0 to 11 kW, or 0 to 22 kW).

Wireless power transmitter 102 converts power from an external powersource (e.g., power grid or generator) to electromagnetic energy whichis transmitted between resonators 108T and 108R to wireless powerreceiver 104. Receiver 104 converts the oscillating energy received byresonator 108R to an appropriate form for use by device 112 (e.g.,charging an electric vehicle battery). More specifically, the receiverpower and control circuitry 110 can convert AC voltage and current fromresonator 108R to DC power within appropriate voltage and currentparameters for device 112.

The transmitter power and control circuitry 106 can include circuits andcomponents to isolate the source electronics from the power supply, sothat any reflected power or signals are not coupled out through thesource input terminals. The source power and control circuitry 106 candrive the source resonator 108S with alternating current, such as with afrequency greater than 10 kHz and less than 100 MHz (e.g., 85 kHz). Thesource power and control circuitry 106 can include, for example, powerfactor correction (PFC) circuitry, a transmitter controller, impedancematching circuitry, a power inverter, a DC-to-DC converter, an AC-to-DCconverter, a power amplifier, or any combination thereof.

The receiver power and control circuitry 110 can be designed totransform alternating current power from the receiver resonator 108R tostable direct current power suitable for powering or charging one ormore devices 112. For example, the receiver power and control circuitry110 can be designed to transform an alternating current power at onefrequency (e.g., 85 kHz) from resonator 108R to alternating currentpower at a different frequency suitable for powering or charging one ormore devices 112. The receiver power and control circuitry 110 caninclude, for example, a receiver controller, impedance matchingcircuitry, rectification circuitry, voltage limiting circuitry, currentlimiting circuitry, AC-to-DC converter circuitry, DC-to-DC convertercircuitry, DC-to-AC circuitry, AC-to-AC converter circuitry, and batterycharge control circuitry.

Transmitter 102 and receiver 104 can have tuning capabilities, forexample, dynamic impedance matching circuits, that allow adjustment ofoperating points to compensate for changing environmental conditions,perturbations, and loading conditions that can affect the operation ofthe source and device resonators and the efficiency of the energytransfer. The tuning capability can be controlled automatically, and maybe performed continuously, periodically, intermittently or at scheduledtimes or intervals. In some implementations, tuning is performedsynchronously between the transmitter 102 and the receiver 104 asdescribed in more detail below.

FIG. 1B shows the power and control circuitry 106 and 110 of transmitter102 and receiver 104 in more detail. Referring to both FIGS. 1A and 1B,transmitter 102 includes an inverter 122 powering a transmitterimpedance matching network (IMN) 124 and a controller 125 that controlsthe operation of inverter 122 and tunes transmitter IMN 124. TransmitterIMN 124 is coupled to resonator coil 108T. Receiver 104 includes areceiver IMN 126 coupled to resonator 108R, a rectifier 128 and acontroller 129 that can tune the receiver IMN 126. In operation,inverter 122 provides power through transmitter IMN 124 to resonator108T. Resonator 108T couples oscillating electromagnetic energy toresonator 108R, with a coupling constant k. The energy received byresonator 108R is transferred through receiver IMN 126 to rectifier 108which converts the energy into an appropriate form for use by device112.

Transmitter controller 125 and receiver controller 129 can beimplemented as processors or microcontrollers. In some implementations,transmitter controller 125 and receiver controller 129 can beimplemented as ASIC or FPGA controllers. Transmitter controller 125 andreceiver controller 129 need not be implemented in the same form. Forexample, transmitter controller 125 can be implemented as amicrocontroller and receiver controller 129 can be implemented as anASIC controller.

Transmitter 102 also includes a plurality of sensors such as voltage,current, and power sensors to measure transmitter operating parameters.Transmitter controller 125 can use measurements from the sensors tocontrol the operation of the transmitter 102 and to tune the transmitterIMN 124. Transmitter operating parameters measured by the sensors caninclude, but is not limited to, inverter bus voltage (V_(bus)),transmitter input power, inverter AC voltage (V_(AC)), inverter ACcurrent (I_(AC)), transmitter power factor (pf), and other voltages andcurrents as needed for safety checks. In some implementations, thetransmitter input power is measured at an AC input to a transmitter PFCcircuit. In some implementations, the transmitter input power ismeasured as an inverter power (P_(in)), as shown in FIG. 1B. In someimplementations, the inverter power (P_(in)) is measured at the DC inputof inverter 122. In some implementations, inverter power (P_(in)) ismeasured at the AC output of inverter 122. Transmitter power factor canbe measured as the phase difference (φ) between the inverter AC voltage(V_(AC)) and inverter AC current (I_(AC)), where the power factor is thecosine of the phase difference (φ). In some implementations, the phasedifference (φ) can be used as a proxy for power factor. That is,transmitter controller 125 can perform operations based on the phasedifference (φ) instead of calculating an actual power factor value. Insome implementations, transmitter power factor (pf) can be calculatedbased on equivalent resistance and reactance values as seen at theoutput of the inverter. For example, the phase difference (φ) can berepresented by:φ=arctan(X _(inverter) /R _(inverter)).

Receiver 104 also includes a plurality of sensors such as voltage,current, and power sensors to measure receiver operating parameters.Receiver controller 129 can use measurements from the sensors to controlthe operation of the receiver 104 and to tune the receiver IMN 126.Receiver operating parameters measured by the sensors can include, butis not limited to, receiver output power (P_(out)), rectifier ACvoltage, rectifier AC current, rectifier DC voltage, rectifier DCcurrent, and other voltages and currents as needed for safety checks.

Transmitter IMN 124 and receiver IMN 126 can each include a plurality offixed and variable impedance matching components such as resistors,capacitors, inductors, or combinations thereof. Variable impedancecomponents can be tunable reactive impedance components including, butnot limited to, PWM-switched capacitors, radio frequency (RF) controlledcapacitors whose effective capacitance at RF is controlled by a DC biasfield, temperature-controlled capacitors, PWM-switched inductors, DCcontrolled inductors whose effective inductance is controlled by a biasDC field (e.g., a saturable core), temperature-controlled inductors,arrays of reactive elements switched in and out of the circuit byswitches, or a combination thereof.

In the illustrated example, transmitter IMN 124 includes seriescapacitor 132, parallel capacitor 134, and the combination of capacitor136 and inductor 138 at the output of inverter 122. Capacitor 136 is avariable capacitor and can include one or more variable capacitors. Aresistive component of the transistor resonator coil 108T is representedby resistor 140.

Receiver IMN 126 includes series capacitor 144, parallel capacitor 146,and the combination of capacitor 148 and inductor 150 at the input torectifier 128. Capacitor 148 is a variable capacitor and can include oneor more variable capacitors. A resistive component of the receiverresonator coil 108R is represented by resistor 152.

IMNs 124 and 126 can have a wide range of circuit implementations withvarious components having impedances to meet the needs of a particularapplication. For example, U.S. Pat. No. 8,461,719 to Kesler et al.,which is incorporated herein by reference in its entirety, discloses avariety of tunable impedance network configurations, such as in FIGS.28a-37b . In some implementations, each of the components shown in FIG.1B may represent networks or groups of components.

Each of the IMNs 124 and 126 include three reactances: series reactanceX1 (e.g., capacitor 132 or 144), parallel reactance X2 (e.g., capacitor134 or 146), and inverter output/rectifier input reactance X3 (combinedreactance of inductor 138 or 150 with capacitor 136 or 148,respectively). The reactances X1-X3 of receiver IMN 126 mirror thecorresponding reactances X1-X3 of transmitter IMN 124. Althoughreactance X3 is the only reactance illustrated as including a tunablereactance component, namely, capacitors 136 and 148, in otherimplementations, reactances X1 and X2 can include tunable reactancecomponents in addition to or in place of the tunable reactance componentin reactance X3. In other words, IMNs 124 and 126 can be tuned by tuningany one or more of reactances X1-X3. In some implementations, componentsthat make up reactances X1 and X3 can be balanced.

While any of reactances X1, X2, X3, or combinations thereof can betuned, in some implementations, it can be advantageous to tune reactanceX3. For example, by tuning reactance X3, it may be possible to reducesystem complexity and cost if tuning a single component in IMN issufficient. By tuning reactance X3, the current through the X3 elementscan be significantly lower than that through the tank circuit formed byX1, X2, and the resonator coil. This lower current may makeimplementation of tunable components more cost-effective by, forexample, reducing current ratings that may be required for suchcomponents. Additionally, lower currents may reduce losses by tuningelements at X3.

In some implementations, tunable reactive elements (e.g., PWM controlledcapacitors) can inject harmonic noise into a HRWPT system. To help withEMI compliance, may be preferable to keep this harmonic noise away fromthe main HRWPT resonator coils (e.g., 108T and 108R). Higher-harmonicsinjected by a tunable element at X3 may be more suppressed than thosethat can be generated by the inverter and rectifier and may besignificantly suppressed by the rest of the HRWPT circuit beforereaching the resonator coil 108T or 108R.

In some implementations with tunable elements at X3 (e.g., PWMcontrolled capacitors), the tunable element dissipates the least amountof power (theoretically zero) when the overall efficiency of the rest ofthe system is lowest, and the highest amount of power when the overallefficiency of the rest of system is highest. This has the desirableeffect of optimizing the minimum and average efficiencies of the systemwhile only slightly affecting the maximum efficiency. However, tuningelements at X1 or X2 can have the opposite, less desirable, effect.

Fixed reactances of X1 and X2, and the base reactance value of X3 can beselected to achieve the results shown in FIGS. 2A-2D and discussedbelow. For example, values for X1 and X2 can be determined by: 1)Determining the maximum range of reactive tuning that can be achievedbased on the maximum current that flows through the circuit branchescontaining X3 and the current and voltage ratings of the components usedin the implementation of the tunable reactive elements. For example, onemay conclude that a single-stage reactive element can affect 20Ω ofreactive tuning. 2) Optimizing, for the receiver-side IMN, X1, X2, andthe base value of X3 so as to optimize the coil-to-coil efficiency overthe range of relative positions of the resonators (and of loadconditions) and/or ensure that the amount of power dissipated in theresonators stays below a specified limit based on the range of reactivedetermined in step 1. 3) Optimizing, for the transmitter-side IMN, X1,X2, and the base value of X3 so as to present a desirable effectiveimpedance to the inverter (e.g., sufficiently inductive to achievezero-voltage-switching in a Class D inverter, but not too inductive thatthere's excessive reactive current, and with a magnitude that fallswithin the range of bus voltages that can be practically achieved).

FIGS. 2A-2D illustrate plots related to the effects of tuning receiverX3. FIG. 2A shows source (transmitter) resonator power losses (in W perkW to the load) as a function of quality factor ratio Q_(d) ^(U)/Q_(d)^(L), where Q_(d) ^(U) is the quality factor of the unloaded device(receiver) resonator and Q_(d) ^(U) is the quality factor of the loadeddevice loaded device resonator (loading includes the loading of theremaining device circuitry and load) and figure of meritF_(oM)=U=k√{square root over (Q_(s)Q_(d))}. FIG. 2A illustrates thatfigure of merit plays a dominate role in losses at the transmitterresonator.

FIG. 2B shows device resonator power losses (in W per kW to the load) asa function of quality factor ratio Q_(d) ^(U)/Q_(d) ^(L) where Q is thequality factor of the unloaded device resonator and Q_(d) ^(L) is thequality factor of the loaded device resonator (loading includes theremaining device circuitry and load) and figure of meritF_(oM)=U=k√{square root over (Q_(s)Q_(d))}. FIG. 2B illustrates thatquality factor ratio plays a dominate role in losses at the receiverresonator.

FIG. 2C shows device figure of merit U_(d) at an operating frequency of84 kHz as a function of the change in reactance dX (in ohms) at positionX3 and load resistance R_(L) (in ohms). Figure of merit U_(d) is definedthrough:

$\frac{R_{L,{eq}}}{R_{d}} = \sqrt{1 + U_{d}^{2}}$where R_(L,eq) is the loaded equivalent series resistance (ESR) (due todevice electronics, such as the rectifier, and battery) of the deviceresonator and R_(d) is the unloaded ESR of the device resonator. WhenU_(d) is set to equal figure of merit U of the system, then thecoil-to-coil efficiency can be maximized.

FIG. 2D shows phase ψ (in degrees) at an operating frequency of 84 kHzas a function of the change in reactance (in ohms) and load resistance(in ohms). Phase ψ is defined by:

$\psi = {\arctan\left( \frac{\Delta\; X_{L}}{R_{L,{eq}}} \right)}$where ΔX_(L) is the residual reactance of the loaded device resonator atthe operating frequency. A phase ψ=0 means the loaded device resonatoris at resonance.

The trapezoidal dotted outline 202 in FIGS. 2C and 2D shows an operatingrange for a wireless power transfer receiver. Outline 202 in FIG. 2Dshows a range of R_(L) that would be seen for a wireless powertransmission system operating at 11 kW output. For example, forR_(L)=10Ω, there is a significant ability to tune X3, as shown in FIG.2C by range of dX at R_(L)=10Ω, while maintaining near resonance (oravoiding detuning the resonator), as shown in FIG. 2D by the proximityof ψ=0 curve to R_(L)=10Ω.

Referring again to FIG. 1B, controllers 125 and 129 can synchronouslytune the IMNs 124 and 126, respectively, to maintain system 100operations within desired operating ranges such as outline 202. In theillustrated implementations, controllers 125 and 129 perform theprocesses described below to synchronously tune reactance X3 of thetransmitter and receiver IMNs 124 and 126 in order to safely andefficiently transfer power to a device 112 such as an electric vehicle.In order to synchronously control the IMNs 124 and 126, transmitter 102and receiver 104 can communicate control data between each other. Forexample, controllers 125 and 129 can include wireless communicationinterfaces to conduct electronic communications in an out-of-bandcommunications channel. Communications between controllers 125 and 129can include, but are not limited to, RF communications (e.g., WiFI,Bluetooth, Zigbee), optical communication, infrared communications,ultrasonic communications, or a combination thereof.

For example, as described in more detail below in reference to FIGS.3-5C, controller 125 can tune transmitter IMN 124 to achieve a targetpower characteristics of transmitter 102, while controller 129 can tunereceiver IMN 126 to achieve a target system efficiency. Transmittercontroller 125 adjusts IMN 124 to achieve and maintain target powercharacteristics of the transmitter 102. Transmitter controller 125 sendsinput power data to receiver controller 129. Receiver controller 129measures output power of the receiver 104 and, together with the inputpower data, calculates the efficiency of the system 100. Receivercontroller 129 tunes the receiver IMN 126 to maximize the systemefficiency. For example, receiver controller 129 can determineappropriate adjustments to receiver IMN 126 based on comparing acalculated efficiency values at two different times.

In some implementations, transmitter controller 125 operates at a fasterrate than receiver controller 129. That is, transmitter controller 125can tune the transmitter IMN 124 at a faster rate than receivercontroller 129 can tune the receiver IMN 126. For example, receivercontroller 129 may only be permitted to tune receiver IMN 126 as fast asit receives new input power data from transmitter controller 125.

FIG. 3 depicts a flowchart of an exemplary control process 300 foroperating a wireless power transmission system. In some examples, theexample process 300 can be provided as computer-executable instructionsexecuted using one or more processing devices (e.g., processors ormicrocontrollers) or computing devices. In some examples, the process300 may be executed by hardwired electrical circuitry, for example, asan ASIC or an FPGA controller.

Portions of process 300 are be performed by a wireless power transmitter102 (e.g., transmitter controller 125) and portions of process 300 areperformed by a wireless power receiver 104 (e.g., receiver controller129). Process 300 includes two control loops 303 and 305. Loop 303 isperformed by a transmitter 102 to tune a transmitter IMN 124 byadjusting reactance X3 to control the transmitter power. In someimplementations, loop 303 is a local loop that does not requirecommunication with other devices (e.g., receiver 104) to be performed.In some implementations, loop 303 is executed by a transmitter atbetween 1-10 kHz. Loop 303 can be characterized by:

$P_{in} = {\frac{\frac{8}{\pi^{2}}V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}}R_{inv}}$where P_(in) is the power of the inverter, V_(bus) is the DC bus voltageof the inverter 122, R_(inv) is the effective resistance as seen by theinverter, and X_(inv) is the effective reactance as seen by theinverter.

Loop 305 is performed by a receiver 104 to tune a receiver IMN 126 basedon system efficiency. For example, loop 305 can employ a“perturb-and-observe” strategy to improve efficiency by adjustingreactance X3 of a receiver IMN 126 to continually improve efficiencyover consecutive iterations. Loop 305 depends on input power data fromtransmitter 102 to calculate system efficiency at each iteration. Insome implementations, loop 305 operates at the rate of communicationbetween transmitter 102 and receiver 104, for example, 40 Hz.

Block 302 lists the inputs and initial conditions for process 300 whichinclude a variable transmitter reactance X_(tx) (e.g., X3 of transmitterIMN 124), set to a maximum reactance value X_(tx,max); a variablereceiver reactance Xrx (e.g., X3 of receiver IMN 126), set to a minimumreactance value X_(rx,min); a system efficiency η, initially set tozero; a transmitter reactance step size ΔX_(tx), set to an adjustmentvalue of 6; and a receiver reactance step size ΔX_(rx), set to anadjustment value of ε. In some implementations, the reactance step sizesΔX_(tx) and ΔX_(rx) are constant values. In some implementations, thereactance step sizes ΔX_(tx) and ΔX_(rx) can be variable. For example,controller 125 or controller 129 can increase or decrease the magnitudeof the respective step sizes dynamically during process 300.

Process 300 starts at step 304. At step 306 the power of the transmitter102 is measured. Transmitter controller 125 measures the input powerP_(in), and, at step 306, compares the input power P_(in) to a targetpower level P_(target). If P_(in) equals P_(target) the process 300proceeds to step 308 of loop 305. If P_(in) does not equal P_(target),process 300 proceeds to step 316 of loop 303. In some implementations orsome operation modes, the target power level is set by the transmitter102. In some implementations or some operation modes, the target powerlevel is set by the receiver 104. For example, when in steady-stateoperations (e.g., normal operations apart from startup or shutdownsequences), system 100 can operate as a demand based system. Forexample, receiver 104 can request power levels from the transmitter 102.Transmitter controller 125 can calculate a target input power levelbased on the demanded power level from the receiver 104. For example,transmitter controller 125 can convert the demanded power to a targetinput power level that would be required to transmit the demanded powerlevel by accounting for expected losses in the transmitter (e.g., IMNlosses and inverter losses).

Referring first to the transmitter-side loop, loop 303, if the inputpower of the transmitter (e.g., the inverter power) is not equal to thetarget power, at step 316 transmitter controller 125 compares the inputpower to the target power level to determine whether the input power isless than the target power level. If P_(in) is less than P_(target),then, at step 318, transmitter controller 125 sets the transmitterreactance step size ΔX_(tx), to a negative adjustment value to decreasethe variable transmitter reactance X_(tx) in step 320. If P_(in) is notless than P_(target), then, at step 322, transmitter controller 125 setsthe transmitter reactance step size ΔX_(tx), to a positive adjustmentvalue to increase the variable transmitter reactance X_(tx) in step 320.In some implementations, the magnitude of the reactance adjustment valueδ can be varied. For example, if the difference between P_(in) andP_(target) is large, for example, greater than a coarse adjustmentthreshold value, then the transmitter controller 125 can increase themagnitude of the reactance adjustment value δ. Correspondingly, if thedifference between P_(in) and P_(target) is small, for example, lessthan a fine adjustment threshold value, then the transmitter controller125 can decrease the magnitude of the reactance adjustment value δ.After the variable transmitter reactance X_(tx) is adjusted in step 320,loop 303 returns to step 306, where the input power is again compared tothe target power level.

Referring to the receiver-side loop, loop 305, if the input power of thetransmitter is equal to the target power, at step 308, the receivercontroller 129 measures the efficiency of the system 100. For example,when P_(in) is equal to P_(target), the transmitter can send dataindicating the measured value of P_(in) to the receiver 104. (It shouldbe noted that measured transmitter power can be represented by afloating point number and, thus, may not exactly equal the target power,but may be equivalent within a predetermined tolerance.) Receivercontroller 129 measures the output power of the receiver, and calculatesthe system efficiency η(n) at time n based on the received transmitterpower data and the measured receiver output power value.

At step 310, receiver controller 129 compares the system efficiencycalculated at time n, to the system efficiency calculated at a previoustime n−1. If the efficiency at time n is greater than the efficiency attime n−1, then, at step 312, the variable receiver reactance X_(rx) isadjusted by the receiver reactance step size ΔX_(rx). For example, thechange in receiver reactance ΔX_(rx) is added to the variable receiverreactance X_(rx). If the efficiency at time n is not greater than theefficiency at time n−1, then, at step 314, receiver controller 129changes the sign of the receiver reactance step size ΔX_(rx) beforeadjusting the variable receiver reactance X_(rx) at step 312. Forexample, the value of the change in receiver reactance ε can be negated.For example, the direction of adjustments for the variable receiverreactance X_(rx) is swapped when the efficiency is no longer increasingbetween subsequent iterations of loop 305. As illustrated in by loop305, direction of adjustments for the variable receiver reactance X_(rx)will then be retained in subsequent iterations of loop 305 untilefficiency decreases again, thereby, maintaining a near-maximum systemefficiency.

In some implementations, the magnitude of the reactance adjustment valueε can be varied. For example, if the efficiency at time n is less than acoarse adjustment threshold value (e.g., soon after system startup),then the receiver controller 129 can increase the magnitude of thereactance adjustment value E. Correspondingly, if the efficiency at timen is near an estimated maximum value for example, within a fineadjustment threshold of the estimated maximum value, then the receivercontroller 129 can decrease the magnitude of the reactance adjustmentvalue ε.

FIG. 4 depicts a flowchart of an exemplary control process 400 foroperating a wireless power transmission system. In some examples, theexample process 400 can be provided as computer-executable instructionsexecuted using one or more processing devices (e.g., processors ormicrocontrollers) or computing devices. In some examples, the process400 may be executed by hardwired electrical circuitry, for example, asan ASIC or an FPGA controller.

Process 400 is similar to process 300, but includes control of inverterbus voltage V_(bus) to adjust transmitter power P_(in), and measurementsof and the use of inverter power factor (e.g., inverter AC voltageV_(AC) and inverter AC current I_(AC) phase difference φ) to tune thetransmitter IMN 124.

Portions of process 400 are be performed by a wireless power transmitter102 (e.g., transmitter controller 125) and portions of process 400 areperformed by a wireless power receiver 104 (e.g., receiver controller129). Process 400 includes three control loops 401, 403, and 405. Loops401 and 403 are performed by a transmitter 102 to tune a transmitter IMN124 and to control the transmitter power. Loop 401 is a phase loop thattunes the transmitter IMN 124 by adjusting reactance X3 to achieve atarget phase φ relationship between the inverter AC output voltage andinverter AC output current (e.g., inverter power factor), hereinafterreferred to as “inverter output phase φ_(inv)” and “target inverteroutput phase φ_(target).” Loop 403 is a power control loop that controlsand maintains the transmitter power magnitude P_(in) at or near thetarget power P_(target) by adjusting the inverter bus voltage V_(bus).In some implementations, loops 401 and 403 are local loops that do notrequire communication with other devices (e.g., receiver 104) to beperformed. In some implementations, loops 401 and 403 are executed by atransmitter at between 1-10 kHz. Loops 401 and 403 can be characterizedby:

$P_{in} = {\frac{\frac{8}{\pi^{2}}V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}}R_{inv}}$where P_(in) is the power of the inverter, V_(bus) is the DC bus voltageof the inverter 122, R_(inv) is the effective resistance as seen by theinverter, and X_(inv) is the effective reactance as seen by theinverter.

Loop 405 is performed by a receiver 104 to tune a receiver IMN 126 basedon system efficiency. Loop 405 is similar to loop 305 of process 300.For example, loop 405 can employ a “perturb-and-observe” strategy toimprove efficiency by adjusting reactance X3 of a receiver IMN 126 tocontinually improve efficiency over consecutive iterations. Loop 405depends on input power data from transmitter 102 to calculate systemefficiency at each iteration. In some implementations, loop 405 operatesat the rate of communication between transmitter 102 and receiver 104,for example, 40 Hz.

Block 402 lists the inputs and initial conditions for process 400 whichinclude a variable transmitter reactance X_(tx) (e.g., X3 of transmitterIMN 124), set to a maximum reactance value X_(tx,max); a variablereceiver reactance X_(rx) (e.g., X3 of receiver IMN 126), set to aminimum reactance value X_(rx,min); a system efficiency η, initially setto zero; a transmitter reactance step size ΔX_(tx), set to an adjustmentvalue greater than zero; a receiver reactance step size ΔX_(rx), set toan adjustment value greater than zero; and a bus voltage step sizeΔV_(bus) set to an adjustment value greater than zero. In someimplementations, the reactance step sizes ΔX_(tx) and ΔX_(rx) and busvoltage step size ΔV_(bus) are constant values. In some implementations,the reactance step sizes ΔX_(tx) and ΔX_(rx) and bus voltage step sizeΔV_(bus) can be variable. For example, controller 125 or controller 129can increase or decrease the magnitude of the respective step sizesdynamically during process 400.

Process 400 starts at step 404. At step 406, transmitter controller 125measures the inverter output phase φ_(inv), and compares the measuredinverter output phase φ_(inv) to a target inverter output phaseφ_(target). If φ_(inv) equals φ_(target) the process 400 proceeds tostep 408 of loop 403. If φ_(inv) does not equal φ_(target) the process400 proceeds to step 424 of loop 401. In some implementations,φ_(target) is slightly greater than 0 so the inverter still sees aslightly inductive load.

Referring first to phase loop, loop 401, if the inverter output phase isnot equal to the target inverter output phase, at step 406 transmittercontroller 125 compares the inverter output phase to the target inverteroutput phase, at step 424, to determine whether the inverter outputphase is greater than the target inverter output phase. If φ_(inv) isgreater than φ_(target), then, at step 426, transmitter controller 125checks whether the variable transmitter reactance X_(tx) is already at aminimum value X_(tx,min). If the variable transmitter reactance X_(tx)is already at a minimum value X_(tx,min), then loop 401 proceeds to step408 with no adjustment to the variable transmitter reactance X_(tx). Ifthe variable transmitter reactance X_(tx) is not at a minimum valueX_(tx,min), then, at step 332, transmitter controller 125 decrements thevariable transmitter reactance X_(tx) by the transmitter reactance stepsize ΔX_(tx), and loop 401 reverts back to step 406 to reevaluate theinverter output phase.

If, at step 424, φ_(inv) is not greater than φ_(target), then, at step430, transmitter controller 125 checks whether the variable transmitterreactance X_(tx) is already at a maximum value X_(tx,max). If thevariable transmitter reactance X_(tx) is already at a maximum valueX_(tx,max), then loop 401 proceeds to step 408 with no adjustment to thevariable transmitter reactance X_(tx). If the variable transmitterreactance X_(tx) is not at a maximum value X_(tx,max), then, at step420, transmitter controller 125 increments the variable transmitterreactance X_(tx) by the transmitter reactance step size ΔX_(tx), andloop 401 reverts back to step 406 to reevaluate the inverter outputphase.

Referring to the power loop, loop 403, at step 408 transmittercontroller 125 measures the input power P_(in), and compares themeasured input power P_(in) to a target power level P_(target). IfP_(in) equals P_(target) the process 400 reverts to step 406 of loop401. In addition, transmitter controller 125 can send data indicatingthe measured value of P_(in) to the receiver 104. If P_(in) does notequal P_(target), process 400 proceeds to step 418. In someimplementations or some operation modes, the target power level is setby the transmitter 102. In some implementations or some operation modes,the target power level is set by the receiver 104. For example, when insteady-state operations (e.g., normal operations apart from startup orshutdown sequences), system 100 can operate as a demand based system.For example, receiver 104 can request power levels from the transmitter102. Transmitter controller 125 can calculate a target input power levelbased on the demanded power level from the receiver 104. For example,transmitter controller 125 can convert the demanded power to a targetinput power level that would be required to transmit the demanded powerlevel by accounting for expected losses in the transmitter (e.g., IMNlosses and inverter losses).

If the power of the transmitter is not equal to the target power, atstep 418 transmitter controller 125 compares the input power to thetarget power level to determine whether the input power is less than thetarget power level. If P_(in) is less than P_(target), then, at step420, transmitter controller 125 increments the inverter bus voltageV_(bus) by the bus voltage step size ΔV_(bus), and loop 403 reverts backto step 408 to reevaluate the power of the transmitter. If P_(in) is notless than P_(target), then, at step 422, transmitter controller 125decrements the inverter bus voltage V_(bus) by the bus voltage step sizeΔV_(bus), and loop 403 reverts back to step 408 to reevaluate the powerof the transmitter.

In some implementations, the magnitude of the transmitter reactance stepsize ΔX_(tx) can be varied. For example, if the difference betweenφ_(inv) and φ_(target) is large, for example, greater than a coarseadjustment threshold value, then the transmitter controller 125 canincrease the transmitter reactance step size ΔX_(tx). Correspondingly,if the difference between φ_(inv) and φ_(target) is small, for example,less than a fine adjustment threshold value, then the transmittercontroller 125 can decrease the magnitude of the transmitter reactancestep size ΔX_(tx).

In some implementations, the magnitude of the bus voltage step sizeΔV_(bus) can be varied. For example, if the difference between P_(in)and P_(target) is large, for example, greater than a coarse adjustmentthreshold value, then the transmitter controller 125 can increase thebus voltage step size ΔV_(bus). Correspondingly, if the differencebetween P_(in) and P_(target) is small, for example, less than a fineadjustment threshold value, then the transmitter controller 125 candecrease the magnitude of the bus voltage step size ΔV_(bus).

Referring to the receiver-side loop, loop 405, at step 409 receiver 104receives transmitter power data. For example, when P_(in) is equal toP_(target) at step 408, the transmitter 102 can send data indicating themeasured value of P_(in) to the receiver 104. At step 410, the receivercontroller 129 measures the efficiency of the system 100. Receivercontroller 129 measures the output power of the receiver 104, andcalculates the system efficiency η(n) at time n based on the receivedtransmitter power data and the measured receiver output power value.

At step 412, receiver controller 129 compares the system efficiencycalculated at time n, to the system efficiency calculated at a previoustime n−1. If the efficiency at time n is greater than the efficiency attime n−1, then, at step 414, the variable receiver reactance X_(rx) isadjusted by the receiver reactance step size ΔX_(rx). For example, thechange in receiver reactance ΔX_(rx) is added to the variable receiverreactance X_(rx). If the efficiency at time n is not greater than theefficiency at time n−1, then, at step 416, receiver controller 129changes the sign of the receiver reactance step size ΔX_(rx) beforeadjusting the variable receiver reactance X_(rx) at step 414. Forexample, the value of the receiver reactance step size ΔX_(rx) can benegated. For example, the direction of adjustments for the variablereceiver reactance X_(rx) is swapped when the efficiency is no longerincreasing between subsequent iterations of loop 405. As illustrated inby loop 405, direction of adjustments for the variable receiverreactance X_(rx) will then be retained in subsequent iterations of loop405 until efficiency decreases again, thereby, maintaining anear-maximum system efficiency.

In some implementations, the magnitude of the receiver reactance stepsize ΔX_(rx) can be varied. For example, if the efficiency at time n isless than a coarse adjustment threshold value (e.g., soon after systemstartup), then the receiver controller 129 can increase the magnitude ofthe receiver reactance step size ΔX_(rx). Correspondingly, if theefficiency at time n is near an estimated maximum value for example,within a fine adjustment threshold of the estimated maximum value, thenthe receiver controller 129 can decrease the magnitude of the receiverreactance step size ΔX_(rx).

FIGS. 5A-5C depicts a flowchart of an exemplary control processes 500 a,500 b, and 500 c for operating a wireless power transmission system. Insome examples, the processes 500 a, 500 b, and 500 c can be provided ascomputer-executable instructions executed using one or more processingdevices (e.g., processors or microcontrollers) or computing devices. Insome examples, the processes 500 a, 500 b, and 500 c may be executed byhardwired electrical circuitry, for example, as an ASIC or an FPGAcontroller. Processes 500 a, 500 b, and 500 c are related to processes300 and 400, but include additional steps that evaluate and controladditional system parameters to operate a wireless power transmissionsystem.

Referring to FIG. 5A, process 500 a includes portions that are beperformed by a wireless power transmitter 102 (e.g., transmittercontroller 125) and portions that are performed by a wireless powerreceiver 104 (e.g., receiver controller 129). Process 500 a includesthree control loops 501 a, 503 a, and 505. Loops 501 a and 503 a areperformed by a transmitter 102 to tune a transmitter IMN 124 and tocontrol the transmitter power. Loop 501 a is a phase loop that tunes thetransmitter IMN 124 by adjusting reactance X3 to achieve a targetinverter output phase φ_(target). Loop 501 a also includes safety checksto ensure that current, voltage, or other device limitations are notexceeded. Loop 503 a is a power control loop that controls and maintainsthe transmitter power magnitude P_(in) at or near the target powerP_(target) by adjusting the inverter bus voltage V_(bus). Loop 503 aalso incorporates adjustments to inverter frequency f_(inv) to controltransmitter power. In some implementations, loops 501 a and 503 a arelocal loops that do not require communication with other devices (e.g.,receiver 104) to be performed. In some implementations, loops 501 a and503 a are executed by a transmitter at between 1-10 kHz.

Loop 505 is performed by a receiver 104 to tune a receiver IMN 126 basedon system efficiency. Loop 505 is the same as loop 405 of process 400the operation of which is described above.

Block 502 lists the inputs and initial conditions for process 500 awhich include a variable transmitter reactance X_(tx) (e.g., X3 oftransmitter IMN 124), set to a maximum reactance value X_(tx,max); avariable receiver reactance X_(rx) (e.g., X3 of receiver IMN 126), setto a minimum reactance value X_(rx,min); an inverter frequency f_(inv)set to a maximum frequency f_(inv,max); a system efficiency η, initiallyset to zero; a transmitter reactance step size ΔX_(tx), set to anadjustment value greater than zero; a receiver reactance step sizeΔX_(rx), set to an adjustment value greater than zero; an inverterfrequency step size Δf_(inv) set to an adjustment value greater thanzero; and a bus voltage step size ΔV_(bus) set to an adjustment valuegreater than zero. In some implementations, the reactance step sizesΔX_(tx) and ΔX_(rx), bus voltage step size ΔV_(bus), and inverterfrequency step size Δf_(inv) are constant values. In someimplementations, the reactance step sizes ΔX_(tx) and ΔX_(rx), busvoltage step size ΔV_(bus), and inverter frequency step size Δf_(inv)can be variable. For example, controller 125 or controller 129 canincrease or decrease the magnitude of the respective step sizesdynamically during process 500 a.

Process 500 a starts at step 504. At step 506, transmitter controller125 performs several checks while tuning the inverter frequency in step508. Transmitter controller 125 compares the measured input power P_(in)to a target power level P_(target), the measured inverter output phaseφ_(inv) to an inverter output phase limit φ_(limit) (e.g., 45 degrees),and the inverter frequency f_(inv) to the minimum inverter frequencyf_(inv,min). When all of the comparisons in step 506 are true, thentransmitter controller 125 decrements the inverter frequency f_(inv) byinverter frequency step size Δf_(inv) at step 508. If any of thecomparisons are false, the process 500 a proceeds to step 510 of loop501 a.

Referring to phase loop, loop 501 a, if the inverter output phase is notequal to the target inverter output phase, at step 510 transmittercontroller 125 compares the inverter output phase to the target inverteroutput phase, at step 536, to determine whether the inverter outputphase is greater than the target inverter output phase. If φ_(inv) isgreater than φ_(target), then, at step 538, transmitter controller 125performs several additional checks. At step 538, transmitter controller125 checks whether the variable transmitter reactance X_(tx) is alreadyat a minimum value X_(tx,min); whether P_(in) is greater thanP_(target), or whether a safety check has failed. The safety check canbe, for example, an over voltage or over current check. If any of thechecks are true, then loop 501 a proceeds to an additional safety checkat step 540. The safety check at step 540 can be the same safety checkas performed at step 538, for example, to determine whether the safetycheck at step 538 was the check that caused the transmitter controller125 to proceed to step 540. If so, then transmitter controller 125increments the variable transmitter reactance X_(tx) by the transmitterreactance step size ΔX_(tx), and loop 501 a reverts back to step 506. Ifnot, then loop 501 a proceeds to step 512 of loop 503 a to adjust thetransmitter power. If all of the checks at step 538 are false, thentransmitter controller 125 decrements the variable transmitter reactanceX_(tx) by the transmitter reactance step size ΔX_(tx), and loop 501 areverts back to step 506.

Referring back to step 536, if φ_(inv) is not greater than φ_(target),then, at step 546, transmitter controller 125 checks whether thevariable transmitter reactance X_(tx) is already at a maximum valueX_(tx,max). If the variable transmitter reactance X_(tx) is already at amaximum value X_(tx,max), then loop 501 a issue a fault condition 548.If the variable transmitter reactance X_(tx) is not at a maximum valueX_(tx,max), then, at step 550, transmitter controller 125 increments thevariable transmitter reactance X_(tx) by the transmitter reactance stepsize ΔX_(tx), and loop 501 a reverts back to step 506.

Referring to the power loop, loop 503 a, at step 512 transmittercontroller 125 measures the input power P_(in), and compares themeasured input power P_(in) to a target power level P_(target). IfP_(in) equals P_(target) the process 500 a reverts to step 506. Inaddition, transmitter controller 125 can send data indicating themeasured value of P_(in) to the receiver 104. If P_(in) does not equalP_(target) process 500 a proceeds to step 522. At step 522, transmittercontroller 125 compares the input power to the target power level todetermine whether the input power is greater than the target powerlevel. If P_(in) is not greater than P_(target), then, at step 534,transmitter controller 125 increments the inverter bus voltage V_(bus)by the bus voltage step size ΔV_(bus), and loop 503 a reverts back tostep 506. If P_(in) is greater than P_(target), then, at step 524,transmitter controller 125 checks the bus voltage. If the bus voltageV_(bus) is greater than a minimum bus voltage V_(bus,min), then, at step532, transmitter controller 125 decrements the inverter bus voltageV_(bus) by the bus voltage step size ΔV_(bus), and loop 503 a revertsback to step 506.

If, at step 524, the bus voltage V_(bus) is at a minimum bus voltageV_(bus,min), then the transmitter controller 125 reduces the transmitterpower by adjusting either the variable transmitter reactance X_(tx) orthe inverter frequency fin. At step 526, transmitter controller 125checks whether the variable transmitter reactance X_(tx) is already at amaximum value X_(tx,max). If the variable transmitter reactance X_(tx)is not at a maximum value X_(tx,max), then, at step 530, transmittercontroller 125 increments the variable transmitter reactance X_(tx) bythe transmitter reactance step size ΔX_(tx), and loop 501 reverts backto step 506. If the variable transmitter reactance X_(tx) is already ata maximum value X_(tx,max), then the transmitter controller 125 checkswhether the inverter frequency f_(inv) is less than a maximum inverterfrequency f_(inv,max) at step 527. If the inverter frequency f_(inv) isalready at a maximum value f_(inv,max), then loop 503 a reverts to step506 with no adjustments to the bus voltage V_(bus), the variabletransmitter reactance X_(tx), or the inverter frequency f_(inv). If theinverter frequency f_(inv) is not already at a maximum valuef_(inv,max), then, at step 528, transmitter controller 125 incrementsthe inverter frequency f_(inv) by the frequency step size Δf_(inv), andloop 503 a reverts back to step 506.

Referring to FIG. 5B, process 500 b differs from process 500 a bymonitoring and controlling inverter phase shift θ_(inv) instead ofinverter frequency f_(inv). For example, in some implementations,inverter power can be controlled by adjusting the internal phase shiftθ_(inv) between bridge circuits in the inverter. In suchimplementations, a phase shift θ_(inv) of zero degrees may produce aminimum (e.g., zero) inverter power, and a phase shift θ_(inv) of 180degrees may produce a maximum inverter power for a given bus voltageV_(bus). More specifically, in process 500 b steps 560, 562, 564, 566,and 568 replace steps 502, 506, 508, 527, and 528 of process 500 a,respectively.

Process 500 b includes portions that are be performed by a wirelesspower transmitter 102 (e.g., transmitter controller 125) and portionsthat are performed by a wireless power receiver 104 (e.g., receivercontroller 129). Process 500 b includes three control loops 501 b, 503b, and 505. Loops 501 b and 503 b are performed by a transmitter 102 totune a transmitter IMN 124 and to control the transmitter power. Loop501 b is a phase loop that tunes the transmitter IMN 124 by adjustingreactance X3 to achieve a target inverter output phase φ_(target). Loop501 b also includes safety checks to ensure that current, voltage, orother device limitations are not exceeded. Loop 503 b is a power controlloop that controls and maintains the transmitter power magnitude P_(in)at or near the target power P_(target) by adjusting the inverter busvoltage V_(bus). Loop 503 b also incorporates adjustments to inverterphase shift θ_(inv) to control transmitter power. In someimplementations, loops 501 b and 503 b are local loops that do notrequire communication with other devices (e.g., receiver 104) to beperformed. In some implementations, loops 501 b and 503 b are executedby a transmitter at between 1-10 kHz.

Loop 505 is performed by a receiver 104 to tune a receiver IMN 126 basedon system efficiency. Loop 505 is the same as loop 405 of process 400the operation of which is described above.

Block 560 lists the inputs and initial conditions for process 500 bwhich include a variable transmitter reactance X_(tx) (e.g., X3 oftransmitter IMN 124), set to a maximum reactance value X_(tx,max); avariable receiver reactance X_(rx) (e.g., X3 of receiver IMN 126), setto a minimum reactance value X_(rx,min); an inverter phase shiftθ_(inv), set to a minimum phase shift θ_(inv,min); a system efficiencyη, initially set to zero; a transmitter reactance step size ΔX_(tx), setto an adjustment value greater than zero; a receiver reactance step sizeΔθ_(rx), set to an adjustment value greater than zero; an inverter phaseshift step size Δθ_(inv) set to an adjustment value greater than zero;and a bus voltage step size ΔV_(bus) set to an adjustment value greaterthan zero. In some implementations, the reactance step sizes ΔX_(tx) andΔX_(rx), bus voltage step size ΔV_(bus), and inverter phase shift stepsize Δθ_(inv) are constant values. In some implementations, thereactance step sizes ΔX_(tx) and ΔX_(rx), bus voltage step sizeΔV_(bus), and inverter phase shift step size Δθ_(inv) can be variable.For example, controller 125 or controller 129 can increase or decreasethe magnitude of the respective step sizes dynamically during process500 b.

Process 500 b starts at step 504. At step 562, transmitter controller125 performs several checks while tuning the inverter phase shift instep 564. Transmitter controller 125 compares the measured input powerP_(in) to a target power level P_(target) and the inverter phase shiftθ_(inv) to a phase shift limit θ_(limit) (e.g., 180 degrees). When allof the comparisons in step 564 are true, then transmitter controller 125increments the inverter phase shift θ_(inv) by inverter phase shift stepsize Δθ_(inv) at step 564. If any of the comparisons are false, at step582, transmitter controller 125 checks whether the inverter phase shiftθ_(inv) is less than the phase shift limit θ_(limit). If so, process 500b proceeds to step 566. If not, process 500 b proceeds to step 510 ofloop 501 b.

Referring to phase loop, loop 501 b, if the inverter output phase is notequal to the target inverter output phase, at step 510 transmittercontroller 125 compares the inverter output phase to the target inverteroutput phase, at step 536, to determine whether the inverter outputphase is greater than the target inverter output phase. If φ_(inv) isgreater than φ_(target), then, at step 538, transmitter controller 125performs several additional checks. At step 538, transmitter controller125 checks whether the variable transmitter reactance X_(tx) is alreadyat a minimum value X_(tx,min); whether P_(in) is greater thanP_(target), or whether a safety check has failed. The safety check canbe, for example, an over voltage or over current check. If any of thechecks are true, then loop 501 b proceeds to an additional safety checkat step 540. The safety check at step 540 can be the same safety checkas performed at step 538, for example, to determine whether the safetycheck at step 538 was the check that caused the transmitter controller125 to proceed to step 540. If so, then transmitter controller 125increments the variable transmitter reactance X_(tx) by the transmitterreactance step size ΔX_(tx), and loop 501 b reverts back to step 562. Ifnot, then loop 501 b proceeds to step 512 of loop 503 b to adjust thetransmitter power. If all of the checks at step 538 are false, thentransmitter controller 125 decrements the variable transmitter reactanceX_(tx) by the transmitter reactance step size ΔX_(tx), and loop 501 breverts back to step 562.

Referring back to step 536, if φ_(inv) is not greater than φ_(target),then, at step 546, transmitter controller 125 checks whether thevariable transmitter reactance X_(tx) is already at a maximum valueX_(tx,max). If the variable transmitter reactance X_(tx) is already at amaximum value X_(tx,max), then loop 501 b issue a fault condition 548.If the variable transmitter reactance X_(tx) is not at a maximum valueX_(tx,max), then, at step 550, transmitter controller 125 increments thevariable transmitter reactance X_(tx) by the transmitter reactance stepsize ΔX_(tx), and loop 501 b reverts back to step 562.

Referring to the power loop, loop 503 b, at step 512 transmittercontroller 125 measures the input power P_(in), and compares themeasured input power P_(in) to a target power level P_(target). IfP_(in) equals P_(target) the process 500 b reverts to step 562. Inaddition, transmitter controller 125 can send data indicating themeasured value of P_(in) to the receiver 104. If P_(in) does not equalP_(target), process 500 b proceeds to step 522. At step 522, transmittercontroller 125 compares the input power to the target power level todetermine whether the input power is greater than the target powerlevel. If P_(in) is not greater than P_(target), then, at step 534,transmitter controller 125 increments the inverter bus voltage V_(bus)by the bus voltage step size ΔV_(bus), and loop 503 b reverts back tostep 562. If P_(in) is greater than P_(target), then, at step 524,transmitter controller 125 checks the bus voltage. If the bus voltageV_(bus) is greater than a minimum bus voltage V_(bus,min), then, at step532, transmitter controller 125 decrements the inverter bus voltageV_(bus) by the bus voltage step size ΔV_(bus), and loop 503 b revertsback to step 562.

If, at step 524, the bus voltage V_(bus) is at a minimum bus voltageV_(bus,min), then the transmitter controller 125 reduces the transmitterpower by adjusting either the variable transmitter reactance X_(tx) orthe inverter phase shift θ_(inv). At step 526, transmitter controller125 checks whether the variable transmitter reactance X_(tx) is alreadyat a maximum value X_(tx,max). If the variable transmitter reactanceX_(tx) is not at a maximum value X_(tx,max), then, at step 530,transmitter controller 125 increments the variable transmitter reactanceX_(tx) by the transmitter reactance step size ΔX_(tx), and loop 501 breverts back to step 562. If the variable transmitter reactance X_(tx)is already at a maximum value X_(tx,max), then the transmittercontroller 125 checks whether the inverter phase shift θ_(inv) isgreater than a minimum inverter phase shift θ_(inv,min) at step 566. Ifthe inverter phase shift θ_(inv) is already at a minimum valueθ_(inv,min), then loop 503 b reverts to step 562 with no adjustments tothe bus voltage V_(bus), the variable transmitter reactance X_(tx), orthe inverter phase shift θ_(inv). If the inverter phase shift θ_(inv) isnot already at a minimum value θ_(inv,min), then, at step 568,transmitter controller 125 decrements the inverter phase shift θ_(inv)by the phase shift step size Δθ_(inv), and loop 503 b reverts back tostep 562.

Referring to FIG. 5C, process 500 c combines aspects of processes 500 aand 500 b. Process 500 c includes portions that are be performed by awireless power transmitter 102 (e.g., transmitter controller 125) andportions that are performed by a wireless power receiver 104 (e.g.,receiver controller 129). Process 500 c includes three control loops 501c, 503 c, and 505. Loops 501 c and 503 c are performed by a transmitter102 to tune a transmitter IMN 124 and to control the transmitter power.Loop 501 c is a phase loop that tunes the transmitter IMN 124 byadjusting reactance X3 to achieve a target inverter output phaseφ_(target). Loop 501 b also includes safety checks to ensure thatcurrent, voltage, or other device limitations are not exceeded. Loop 503c is a power control loop that controls and maintains the transmitterpower magnitude P_(in) at or near the target power P_(target) byadjusting the inverter bus voltage V_(bus). Loop 503 c also incorporatesadjustments to both inverter frequency f_(inv) and inverter phase shiftθ_(inv) to control transmitter power. In some implementations, loops 501c and 503 c are local loops that do not require communication with otherdevices (e.g., receiver 104) to be performed. In some implementations,loops 501 c and 503 c are executed by a transmitter at between 1-10 kHz.

Loop 505 is performed by a receiver 104 to tune a receiver IMN 126 basedon system efficiency. Loop 505 is the same as loop 405 of process 400the operation of which is described above.

Block 580 represents the inputs and initial conditions for process 500 cwhich include a variable transmitter reactance X_(tx) (e.g., X3 oftransmitter IMN 124), set to a maximum reactance value X_(tx,max); avariable receiver reactance X_(rx) (e.g., X3 of receiver IMN 126), setto a minimum reactance value X_(rx,min); an inverter frequency f_(inv),set to a maximum frequency f_(inv,max); an inverter phase shift θ_(inv),set to a minimum phase shift θ_(inv,min); a system efficiency η,initially set to zero; a transmitter reactance step size ΔX_(tx), set toan adjustment value greater than zero; a receiver reactance step sizeΔX_(rx), set to an adjustment value greater than zero; an inverterfrequency step size Δf_(inv) set to an adjustment value greater thanzero; an inverter phase shift step size Δθ_(inv) set to an adjustmentvalue greater than zero; and a bus voltage step size ΔV_(bus) set to anadjustment value greater than zero. In some implementations, thereactance step sizes ΔX_(tx) and ΔX_(rx), bus voltage step sizeΔV_(bus), inverter frequency step size Δf_(inv), and inverter phaseshift step size Δθ_(inv) are constant values. In some implementations,the reactance step sizes ΔX_(tx) and ΔX_(rx), bus voltage step sizeΔV_(bus), inverter frequency step size Δf_(inv), and inverter phaseshift step size Δθ_(inv) can be variable. For example, controller 125 orcontroller 129 can increase or decrease the magnitude of the respectivestep sizes dynamically during process 500 c.

Process 500 c starts at step 504. At step 562, transmitter controller125 performs several checks while tuning the inverter phase shift instep 564. Transmitter controller 125 compares the measured input powerP_(in) to a target power level P_(target) and the inverter phase shiftθ_(inv) to a phase shift limit θ_(limit) (e.g., 180 degrees). When allof the comparisons in step 564 are true, then transmitter controller 125increments the inverter phase shift θ_(inv) by inverter phase shift stepsize Δθ_(inv) at step 564. If any of the comparisons are false, at step582, transmitter controller 125 checks whether the inverter phase shiftθ_(inv) is less than the phase shift limit θ_(limit). If so, process 500c proceeds to step 566. If not, process 500 c proceeds to step 506.

At step 506, transmitter controller 125 performs several checks whiletuning the inverter frequency in step 508. Transmitter controller 125compares the measured input power P_(in) to a target power levelP_(target), the measured inverter output phase φ_(inv) to an inverteroutput phase limit φ_(limit) (e.g., 45 degrees), and the inverterfrequency f_(inv) to the minimum inverter frequency f_(inv,min). Whenall of the comparisons in step 506 are true, then transmitter controller125 decrements the inverter frequency f_(inv) by inverter frequency stepsize Δf_(inv) at step 508. If any of the comparisons are false, theprocess 500 a proceeds to step 510 of loop 501 c.

Referring to phase loop, loop 501 c, if the inverter output phase is notequal to the target inverter output phase, at step 510 transmittercontroller 125 compares the inverter output phase to the target inverteroutput phase, at step 536, to determine whether the inverter outputphase is greater than the target inverter output phase. If φ_(inv) isgreater than φ_(target), then, at step 538, transmitter controller 125performs several additional checks. At step 538, transmitter controller125 checks whether the variable transmitter reactance X_(tx) is alreadyat a minimum value X_(tx,min); whether P_(in) is greater thanP_(target), or whether a safety check has failed. The safety check canbe, for example, an over voltage or over current check. If any of thechecks are true, then loop 501 c proceeds to an additional safety checkat step 540. The safety check at step 540 can be the same safety checkas performed at step 538, for example, to determine whether the safetycheck at step 538 was the check that caused the transmitter controller125 to proceed to step 540. If so, then transmitter controller 125increments the variable transmitter reactance X_(tx) by the transmitterreactance step size ΔX_(tx), and loop 501 c reverts back to step 562. Ifnot, then loop 501 c proceeds to step 512 of loop 503 c to adjust thetransmitter power. If all of the checks at step 538 are false, thentransmitter controller 125 decrements the variable transmitter reactanceX_(tx) by the transmitter reactance step size ΔX_(tx), and loop 501 creverts back to step 562.

Referring back to step 536, if φ_(inv) is not greater than φ_(target),then, at step 546, transmitter controller 125 checks whether thevariable transmitter reactance X_(tx) is already at a maximum valueX_(tx,max). If the variable transmitter reactance X_(tx) is already at amaximum value X_(tx,max), then loop 501 c issue a fault condition 548.If the variable transmitter reactance X_(tx) is not at a maximum valueX_(tx,max), then, at step 550, transmitter controller 125 increments thevariable transmitter reactance X_(tx) by the transmitter reactance stepsize ΔX_(tx), and loop 501 c reverts back to step 562.

Referring to the power loop, loop 503 b, at step 512 transmittercontroller 125 measures the input power P_(in), and compares themeasured input power P_(in) to a target power level P_(target). IfP_(in) equals P_(target) the process 500 c reverts to step 562. Inaddition, transmitter controller 125 can send data indicating themeasured value of P_(in) to the receiver 104. If P_(in) does not equalP_(target) process 500 c proceeds to step 522. At step 522, transmittercontroller 125 compares the input power to the target power level todetermine whether the input power is greater than the target powerlevel. If P_(in) is not greater than P_(target), then, at step 534,transmitter controller 125 increments the inverter bus voltage V_(bus)by the bus voltage step size ΔV_(bus), and loop 503 c reverts back tostep 562. If P_(in) is greater than P_(target), then, at step 524,transmitter controller 125 checks the bus voltage. If the bus voltageV_(bus) is greater than a minimum bus voltage V_(bus,min), then, at step532, transmitter controller 125 decrements the inverter bus voltageV_(bus) by the bus voltage step size ΔV_(bus), and loop 503 c revertsback to step 562.

If, at step 524, the bus voltage V_(bus) is at a minimum bus voltageV_(bus,min), then the transmitter controller 125 reduces the transmitterpower by adjusting either the variable transmitter reactance X_(tx), theinverter frequency f_(inv), or the inverter phase shift θ_(inv). At step526, transmitter controller 125 checks whether the variable transmitterreactance X_(tx) is already at a maximum value X_(tx,max). If thevariable transmitter reactance X_(tx) is not at a maximum valueX_(tx,max), then, at step 530, transmitter controller 125 increments thevariable transmitter reactance X_(tx) by the transmitter reactance stepsize ΔX_(tx), and loop 501 c reverts back to step 562.

If the variable transmitter reactance X_(tx) is already at a maximumvalue X_(tx,max), then the transmitter controller 125 checks whether theinverter frequency f_(inv) is less than a maximum inverter frequencyf_(inv,max) at step 527. If the inverter frequency f_(inv) is notalready at a maximum value f_(inv,max), then, at step 528, transmittercontroller 125 increments the inverter frequency f_(inv) by thefrequency step size Δf_(inv), and loop 503 c reverts back to step 562.If the inverter frequency f_(inv) is already at a maximum valuef_(inv,max), then the transmitter controller 125 checks whether theinverter phase shift θ_(inv) is greater than a minimum inverter phaseshift θ_(inv,min) at step 566. If the inverter phase shift θ_(inv) isalready at a minimum value θ_(inv,min), then loop 503 c reverts to step562 with no adjustments to the bus voltage V_(bus), the variabletransmitter reactance X_(tx), or the inverter phase shift θ_(inv). Ifthe inverter phase shift θ_(inv) is not already at a minimum valueθ_(inv,min), then, at step 568, transmitter controller 125 decrementsthe inverter phase shift φ_(inv) by the phase shift step size Δθ_(inv),and loop 503 c reverts back to step 562.

In some implementations, the magnitude of the transmitter reactance stepsize ΔX_(tx) can be varied. For example, if the difference betweenφ_(inv) and φ_(target) is large, for example, greater than a coarseadjustment threshold value, then the transmitter controller 125 canincrease the transmitter reactance step size ΔX_(tx). Correspondingly,if the difference between φ_(inv) and φ_(target) is small, for example,less than a fine adjustment threshold value, then the transmittercontroller 125 can decrease the magnitude of the transmitter reactancestep size ΔX_(tx).

In some implementations, the magnitude of the bus voltage step sizeΔV_(bus) can be varied. For example, if the difference between P_(in)and P_(target) is large, for example, greater than a coarse adjustmentthreshold value, then the transmitter controller 125 can increase thebus voltage step size ΔV_(bus). Correspondingly, if the differencebetween P_(in) and P_(target) is small, for example, less than a fineadjustment threshold value, then the transmitter controller 125 candecrease the magnitude of the bus voltage step size ΔV_(bus).

In some implementations, the magnitude of the inverter frequency stepsize Δf_(inv), can be varied. For example, if the difference betweenP_(in) and P_(target), in step 506, is large, for example, greater thana coarse adjustment threshold value, then the transmitter controller 125can increase the inverter frequency step size Δf_(inv). Correspondingly,if the difference between P_(in) and P_(target) is small, for example,less than a fine adjustment threshold value, then the transmittercontroller 125 can decrease the magnitude of inverter frequency stepsize Δf_(inv).

In some implementations, the magnitude of the inverter phase shift stepsize Δθ_(inv) can be varied. For example, if the difference betweenP_(in) and P_(target), in step 562, is large, for example, greater thana coarse adjustment threshold value, then the transmitter controller 125can increase the inverter phase shift step size Δθ_(inv).Correspondingly, if the difference between P_(in) and P_(target) issmall, for example, less than a fine adjustment threshold value, thenthe transmitter controller 125 can decrease the magnitude of inverterphase shift step size Δθ_(inv).

The following table (Table 1) shows experimental measurements of outputvoltage and efficiency (Eff.) for variations between relative positionsof a wireless power transmitter and receiver for charging an electricvehicle operating according to processes described herein. Position X isthe position of the receiver resonator coil relative to the transmitterresonator coil along the X-axis, where the X-axis runs along a width ofthe vehicle (e.g., driver door to passenger door), and where X=0 is thecenter of transmitter resonator coil. Position Y is the position of thereceiver resonator coil relative to the transmitter resonator coil alongthe Y-axis, where the Y-axis runs along a length of the vehicle (e.g.,front of the vehicle to the rear of the vehicle), and where Y=0 is thecenter of the transmitter resonator coil. Position Z is the separationdistance between the receiver resonator coil and the transmitterresonator coil along the vertical Z-axis.

TABLE 1 Z (mm) X (mm) Y (mm) Vout (V) Eff (%) 160 0 0 280 94.01 160 0 0350 94.46 160 0 0 420 94.42 160 100 75 280 94.03 160 100 75 350 94.32160 100 75 420 93.84 160 150 75 280 93.74 160 150 75 350 94.08 160 15075 420 93.56 190 0 0 280 94.14 190 0 0 350 94.50 190 0 0 420 94.19 190100 75 280 93.81 190 100 75 350 93.75 190 100 75 420 93.11 190 150 75280 93.10 190 150 75 350 93.10 190 150 75 420 91.86 220 0 0 280 93.97220 0 0 350 94.03 220 0 0 420 93.27 220 100 75 280 92.82 220 100 75 35092.52

FIG. 6A depicts a flowchart of an exemplary startup process 600 for awireless power transmission control system. In some examples, theprocess 600 can be provided as computer-executable instructions executedusing one or more processing devices (e.g., processors ormicrocontrollers) or computing devices. In some examples, the process600 may be executed by hardwired electrical circuitry, for example, asan ASIC or an FPGA controller. Some portions of process 600 can beperformed by a wireless power transmitter 102 (e.g., transmittercontroller 125) and some portions of process 600 can be performed by awireless power receiver 104 (e.g., receiver controller 129).

Block 602 lists the inputs and initial conditions for the system startupprocess 600 which include a power factor correction (PFC) stage of atransmitter set to OFF; an inverter pulse width modulation (PWM) set toOFF; an inverter frequency f_(inv) set to a maximum frequencyf_(inv,max); a variable transmitter reactance X_(tx) (e.g., X3 oftransmitter IMN 124) set to a maximum reactance value X_(tx,max); and avariable receiver reactance X_(rx) (e.g., X3 of receiver IMN 126) set toa maximum reactance value X_(rx,max). The startup process 600 begins atstep 604, the PFC is turned ON and bus voltage V_(bus) is brought tominimum bus voltage V_(bus,min). At step 606, the inverter PWMs areturned ON. At step 608, variable receiver reactance X_(rx) is adjustedto minimum receiver reactance X_(rx,min). At step 610, inverterfrequency f_(inv) is adjusted to target inverter frequencyf_(inv,target). At step 612, the system begins steady state operations,e.g., according to one of processes 300, 400, 500 a, 500 b, or 500 c.

FIG. 6A depicts a flowchart of an exemplary shutdown process 601 for awireless power transmission control system m. In some examples, theprocess 601 can be provided as computer-executable instructions executedusing one or more processing devices (e.g., processors ormicrocontrollers) or computing devices. In some examples, the process601 may be executed by hardwired electrical circuitry, for example, asan ASIC or an FPGA controller. Some portions of process 601 can beperformed by a wireless power transmitter 102 (e.g., transmittercontroller 125) and some portions of process 601 can be performed by awireless power receiver 104 (e.g., receiver controller 129).

Shutdown process 601 begins, at step 612, with the system in steadystate operation, e.g., according to one of processes 300, 400, 500 a,500 b, or 500 c. At step 614, variable receiver reactance X_(rx) isbrought to minimum receiver reactance X_(rx,min). At step 616, variabletransmitter reactance X_(tx) is brought to maximum transmitter reactanceX_(tx,max), and at step 618, bus voltage V_(bus) is brought to minimumbus voltage V_(bus,min). In some implementations, steps 616 and 618 canbe performed directly by a transmitter. In some implementations, steps616 and 618 can be performed indirectly. For example, steps 616 and 618will be performed automatically as part of the steady state operationsof processes 500 a, 500 b, and 500 c (steps 524, 532, 526, and 530)simply be adjusting the target power P_(target) to a shutdown valueP_(shutdown) at step 615. For example, P_(shutdown) can be zero or nearzero. As P_(target) is decreased, the variable transmitter reactanceX_(tx) is brought to maximum transmitter reactance X_(tx,max) and busvoltage V_(bus) is brought to minimum bus voltage V_(bus,min) by thesteady state transmitter operations process. At step 620, the PFC isturned OFF and V_(bus) is brought to 0 V. At step 622, the inverter PWMsare turned off. In some implementations, the wireless communicationbetween the receiver and transmitter may be remain on or be turned offafter power transmission is secured.

While the disclosed techniques have been described in connection withcertain preferred embodiments, other embodiments will be understood byone of ordinary skill in the art and are intended to fall within thescope of this disclosure. For example, designs, methods, configurationsof components, etc. related to transmitting wireless power have beendescribed above along with various specific applications and examplesthereof. Those skilled in the art will appreciate where the designs,components, configurations or components described herein can be used incombination, or interchangeably, and that the above description does notlimit such interchangeability or combination of components to only thatwhich is described herein.

For illustrative purposes, the foregoing description focuses on the useof devices, components, and methods in high power wireless powertransfer applications, e.g., power transfer for charging electricvehicles.

More generally, however, it should be understood that devices that canreceive power using the devices, components, and methods disclosedherein can include a wide range of electrical devices, and are notlimited to those devices described for illustrative purposes herein. Ingeneral, any portable electronic device, such as a cell phone, keyboard,mouse, radio, camera, mobile handset, headset, watch, headphones,dongles, multifunction cards, food and drink accessories, and the like,and any workspace electronic devices such as printers, clocks, lamps,headphones, external drives, projectors, digital photo frames,additional displays, and the like, can receive power wirelessly usingthe devices, components, and methods disclosed herein. Furthermore, anyelectrical device, such as electric or hybrid vehicles, motorized wheelchairs, scooters, power tools, and the like, can receive powerwirelessly using the devices, components, and methods disclosed herein.In addition, the devices, components, and methods disclosed herein maybe used for applications outside of wireless power transfer.

In this disclosure, certain circuit or system components such ascapacitors, inductors, resistors, are referred to as circuit“components” or “elements.” The disclosure also refers to series andparallel combinations of these components or elements as elements,networks, topologies, circuits, and the like. More generally, however,where a single component or a specific network of components isdescribed herein, it should be understood that alternative embodimentsmay include networks for elements, alternative networks, and/or thelike.

As used herein, the equalities and inequalities when referring tocomparisons between transmitter or receiver operating parameters is notintended to require exact equivalence of values, but instead refers toan equivalence of values that are within a threshold or a tolerance ofone another. For example, measured values such as powers, voltages,currents, and phases can be represented and stored as floating pointnumbers. As such, exact equivalence may be unlikely deepening on theprecision of the measurements. Therefore, equivalence between suchnumbers and target values refers to equivalence within a thresholdrange, for example, equivalence within a tolerance of ±1%, ±2%, ±5%, or±10% of the target value. Similarly, inequalities may require a measuredvalue to be greater or less than a target value by an additional ±1%,±2%, ±5%, or ±10% of the target value.

As used herein, the term “coupled” when referring to circuit or systemcomponents is used to describe an appropriate, wired or wireless, director indirect, connection between one or more components through whichinformation or signals can be passed from one component to another.

As used herein, the term “direct connection” or “directly connected,”refers to a direct connection between two elements where the elementsare connected with no intervening active elements between them. The term“electrically connected” or “electrical connection,” refers to anelectrical connection between two elements where the elements areconnected such that the elements have a common potential. In addition, aconnection between a first component and a terminal of a secondcomponent means that there is a path between the first component and theterminal that does not pass through the second component.

Implementations of the subject matter and the operations described inthis specification can be realized in digital electronic circuitry, orin computer software, firmware, or hardware, including the structuresdisclosed in this specification and their structural equivalents, or incombinations of one or more of them. Implementations of the subjectmatter described in this specification can be realized using one or morecomputer programs, i.e., one or more modules of computer programinstructions, encoded on computer storage medium for execution by, or tocontrol the operation of, data processing apparatus. Alternatively or inaddition, the program instructions can be encoded on an artificiallygenerated propagated signal, e.g., a machine-generated electrical,optical, or electromagnetic signal that is generated to encodeinformation for transmission to suitable receiver apparatus forexecution by a data processing apparatus. A computer storage medium canbe, or be included in, a computer-readable storage device, acomputer-readable storage substrate, a random or serial access memoryarray or device, or a combination of one or more of them. Moreover,while a computer storage medium is not a propagated signal; a computerstorage medium can be a source or destination of computer programinstructions encoded in an artificially generated propagated signal. Thecomputer storage medium can also be, or be included in, one or moreseparate physical components or media (e.g., multiple CDs, disks, orother storage devices).

The operations described in this specification can be implemented asoperations performed by a data processing apparatus on data stored onone or more computer-readable storage devices or received from othersources.

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, a system on a chip, or multipleones, or combinations, of the foregoing. The apparatus can includespecial purpose logic circuitry, e.g., an FPGA (field programmable gatearray) or an ASIC (application-specific integrated circuit). Theapparatus can also include, in addition to hardware, code that createsan execution environment for the computer program in question, e.g.,code that constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, a cross-platform runtimeenvironment, a virtual machine, or a combination of one or more of them.The apparatus and execution environment can realize various differentcomputing model infrastructures, such as web services, distributedcomputing and grid computing infrastructures.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, declarative orprocedural languages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, object, orother unit suitable for use in a computing environment. A computerprogram may, but need not, correspond to a file in a file system. Aprogram can be stored in a portion of a file that holds other programsor data (e.g., one or more scripts stored in a markup languagedocument), in a single file dedicated to the program in question, or inmultiple coordinated files (e.g., files that store one or more modules,sub-programs, or portions of code). A computer program can be deployedto be executed on one computer or on multiple computers that are locatedat one site or distributed across multiple sites and interconnected by acommunication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform actions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer can include aprocessor for performing actions in accordance with instructions and oneor more memory devices for storing instructions and data. Generally, acomputer will also include, or be operatively coupled to receive datafrom or transfer data to, or both, one or more mass storage devices forstoring data, e.g., magnetic, magneto-optical disks, or optical disks.However, a computer need not have such devices. Moreover, a computer canbe embedded in another device, e.g., a wireless power transmitter orreceiver or a wirelessly charged or powered device such as a vehicle, amobile telephone, a personal digital assistant (PDA), a mobile audio orvideo player, a game console, or a Global Positioning System (GPS)receiver, to name just a few. Devices suitable for storing computerprogram instructions and data include all forms of non-volatile memory,media and memory devices, including by way of example semiconductormemory devices, e.g., EPROM, EEPROM, and flash memory devices; magneticdisks, e.g., internal hard disks or removable disks; magneto-opticaldisks; and CD-ROM and DVD-ROM disks. The processor and the memory can besupplemented by, or incorporated in, special purpose logic circuitry.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyimplementation of the present disclosure or of what may be claimed, butrather as descriptions of features specific to example implementations.Certain features that are described in this specification in the contextof separate implementations can also be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation can also be implemented inmultiple implementations separately or in any suitable sub-combination.Moreover, although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described program components and systemscan generally be integrated together in a single software product orpackaged into multiple software products.

What is claimed is:
 1. A method of operating a wireless energy transfersystem comprising: tuning, by a wireless energy transmitter, atransmitter impedance matching network (IMN) of the wireless energytransmitter to achieve a target transmitter power characteristic;sending, by the wireless energy transmitter to a wireless energyreceiver, power data that indicates a value of a power level of thewireless energy transmitter; tuning, by the wireless energy receiver andbased on the power data, a receiver-IMN to improve an efficiency of thewireless energy transfer system.
 2. The method of claim 1, wherein thetarget transmitter power characteristic is a target power factor.
 3. Themethod of claim 2, wherein a power factor is represented by a phasedifference between a transmitter voltage and a transmitter current, andwherein the target power factor is a target phase difference.
 4. Themethod of claim 1, further comprising adjusting an inverter bus voltageto achieve a target power magnitude.
 5. The method of claim 1, furthercomprising performing a safety check prior to adjusting thetransmitter-IMN.
 6. The method of claim 5, wherein the safety check isan over-voltage check or an over-current check.
 7. The method of claim1, further comprising: performing, by the wireless energy transmitter, aplurality of checks comprising a check of a magnitude of a transmitterpower, a check of a transmitter power factor, and a check of a frequencyof an inverter in the wireless energy transmitter; and in response tothe plurality checks, selectively adjusting the frequency of theinverter to adjust the power of the wireless energy transmitter.
 8. Themethod of claim 1, further comprising: performing a plurality of checkscomprising a check of a magnitude of a transmitter power and a check ofa phase shift of an inverter of the wireless energy transmitter; and inresponse to the plurality of checks, selectively adjusting the phaseshift of the inverter to adjust the power of the wireless energytransmitter.
 9. The method of claim 1, wherein the wireless energytransmitter is an electric vehicle charger and wherein the wirelessenergy receiver is coupled to a power system of an electric vehicle. 10.The method of claim 1, further comprising adjusting, while starting upthe wireless energy transmitter, a reactance of the transmitter-IMN to amaximum value.
 11. The method of claim 1, further comprising adjusting,while starting up the wireless energy receiver, a reactance of thereceiver-IMN to a minimum value.
 12. The method of claim 2, wherein amagnitude of a step size for adjustments to the transmitter IMN is basedon a difference between a measured power factor and the target powerfactor.
 13. The method of claim 4, wherein a magnitude of a step sizefor adjustments to the inverter bus voltage is based on a differencebetween a measured power magnitude and the target power magnitude. 14.The method of claim 1, further comprising: performing at least one checkcomprising testing an operational limit of the wireless energytransmitter; and in response to the at least one check, selectivelyadjusting a phase shift of an inverter to adjust the power of thewireless energy transmitter.
 15. The method of claim 8, wherein amagnitude of the phase shift of the inverter is based on a differencebetween a measured power characteristic and the target transmitter powercharacteristic.
 16. The method of claim 1, further comprising adjusting,while starting up the wireless energy transmitter, a phase shift of aninverter to a predefined value.
 17. The method of claim 16, wherein thepredefined value is a maximum value.
 18. The method of claim 1, furthercomprising: calculating, by the wireless energy receiver and using thepower data from the wireless energy transmitter, the efficiency of thewireless energy transfer system.
 19. A wireless power transmitter for awireless energy transfer system, the wireless power transmittercomprising: a source resonator; and transmitter power and controlcircuitry coupled with the source resonator to drive the sourceresonator with alternating current, the transmitter power and controlcircuitry comprising a transmitter impedance matching network (IMN), andthe transmitter power and control circuitry being configured to tune thetransmitter-IMN to achieve a target transmitter power characteristic,and send, to a wireless energy receiver, power data that indicates avalue of a power level of the wireless power transmitter, therebycausing the wireless power receiver to tune, based on the power data, areceiver-IMN to improve an efficiency of the wireless energy transfersystem.
 20. The wireless power transmitter of claim 19, comprising oneor more non-transitory computer readable storage media storing firstinstructions, wherein the transmitter power and control circuitry isconfigured to tune the transmitter-IMN and send the power dataresponsive to execution of the first instructions using one or morefirst processing devices, and the wireless power receiver is configuredto tune the receiver-IMN responsive to execution of second instructionsusing one or more second processing devices.